This invention relates to a mechanical transducer which responds to a force which is applied to it in one direction to exert a force of a different magnitude in another direction.
It is a common requirement to control a large force by means of a small force, for example a motor car is brought to rest using a relatively light force applied to a foot brake pedal. It is also a common requirement to take a weak signal and generate sufficient force to operate signalling devices, for example a vane in an air duct can sense very slight air movements yet because of its size it can exert a sufficient force to operate a control switch e.g. in boilers and air conditioning apparatus. However, the necessary control in these examples requires amplifying systems of considerable size and complexity or, in the case of the air valve, lead to possible disturbances from vibration, overshoot or undershoot or time delay if significantly damped. If pistons and similar devices are used as buffers, dampers or actuators, the force-to-thrust ratio is determined by the bore size of the device: in order to contain or to generate large forces the area, and hence the diameter, has to be increased unless unacceptably high pressures are used. However, the increase in bore size, which increases the sensitivity to lower pressures, also results in a considerable increase in the inertia of the axially displaceable piston or cylinder, and this can impair the response and reaction of the apparatus to external shock and vibration forces. For example, a pressure switch (which comprises an electric switch operated by a pressure-sensitive actuator) may use a large circular diaphragm to generate a sufficient force from a low pressure on its surface to overcome the trip force on the switch (which may be a microswitch). This device has the disadvantage that the plane in which the diaphragm lies is perpendicular to the axis of displacement needed to operate the switch and therefore the volume required for the device is large. Also the mass of the diaphragm and other moving parts makes the device vulnerable to axial vibration and therefore to spurious operation.